<html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <meta name="Generator" content="Microsoft Word 15 (filtered medium)"> <style></style> </head> <body lang="en-CN" link="blue" vlink="purple" style="word-wrap:break-word"> <div class="WordSection1"> +Arm folks.<o:p></o:p> <o:p> </o:p> <div id="mail-editor-reference-message-container"> <div> <div> <div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm"> From: Roger Melton (rmelton) <rmelton@cisco.com> Date: Tuesday, December 3, 2024 at 3:39 AM To: dev@dpdk.org <dev@dpdk.org>, Ruifeng Wang <Ruifeng.Wang@arm.com> Subject: lib/eal/arm/include/rte_vect.h fails to compile with clang14 for 32bit ARM<o:p></o:p> </div> Hey folks,<o:p></o:p> We are building DPDK with clang14 for a 32bit armv8-a based CPU and ran into a compile error with the following from lib/eal/arm/include/rte_vect.h:<o:p></o:p> <o:p></o:p> <blockquote style="margin-top:5.0pt;margin-bottom:5.0pt"> <pre>#if (defined(RTE_ARCH_ARM) && defined(RTE_ARCH_32)) || \<o:p></o:p></pre> <pre>(defined(RTE_ARCH_ARM64) && <a href="https://elixir.bootlin.com/dpdk/v24.11/C/ident/RTE_CC_IS_GNU">RTE_CC_IS_GNU</a> && (<a href="https://elixir.bootlin.com/dpdk/v24.11/C/ident/GCC_VERSION">GCC_VERSION</a> < 70000))<o:p></o:p></pre> <pre>/* NEON intrinsic vcopyq_laneq_u32() is not supported in ARMv7-A(AArch32)<o:p></o:p></pre> <pre> * On AArch64, this intrinsic is supported since GCC version 7.<o:p></o:p></pre> <pre> */<o:p></o:p></pre> <pre>static inline uint32x4_t<o:p></o:p></pre> <pre><a href="https://elixir.bootlin.com/dpdk/v24.11/C/ident/vcopyq_laneq_u32">vcopyq_laneq_u32</a>(uint32x4_t a, const int lane_a,<o:p></o:p></pre> <pre> uint32x4_t b, const int lane_b)<o:p></o:p></pre> <pre>{<o:p></o:p></pre> <pre> return vsetq_lane_u32(vgetq_lane_u32(b, lane_b), a, lane_a);<o:p></o:p></pre> <pre>}<o:p></o:p></pre> <pre>#endif<o:p></o:p></pre> </blockquote> clang14 compile fails as follows: <o:p></o:p> <blockquote style="margin-top:5.0pt;margin-bottom:5.0pt"> In file included from ../../../../../../cisco-dpdk-upstream-arm-clang-fixes.git/lib/eal/common/eal_common_options.c:36: ../../../../../../cisco-dpdk-upstream-arm-clang-fixes.git/lib/eal/arm/include/rte_vect.h:80:24: error: argument to '__builtin_neon_vgetq_lane_i32' must be a constant integer return vsetq_lane_u32(vgetq_lane_u32(b, lane_b), a, lane_a); ^ ~~~~~~ /auto/binos-tools/llvm14/llvm-14.0-p24/lib/clang/14.0.5/include/arm_neon.h:7697:22: note: expanded from macro 'vgetq_lane_u32' __ret = (uint32_t) __builtin_neon_vgetq_lane_i32((int32x4_t)__s0, __p1); \ ^ ~~~~ /auto/binos-tools/llvm14/llvm-14.0-p24/lib/clang/14.0.5/include/arm_neon.h:24148:19: note: expanded from macro 'vsetq_lane_u32' uint32_t __s0 = __p0; \ ^~~~ In file included from ../../../../../../cisco-dpdk-upstream-arm-clang-fixes.git/lib/eal/common/eal_common_options.c:36: ../../../../../../cisco-dpdk-upstream-arm-clang-fixes.git/lib/eal/arm/include/rte_vect.h:80:9: error: argument to '__builtin_neon_vsetq_lane_i32' must be a constant integer return vsetq_lane_u32(vgetq_lane_u32(b, lane_b), a, lane_a); ^ ~~~~~~ /auto/binos-tools/llvm14/llvm-14.0-p24/lib/clang/14.0.5/include/arm_neon.h:24150:24: note: expanded from macro 'vsetq_lane_u32' __ret = (uint32x4_t) __builtin_neon_vsetq_lane_i32(__s0, (int32x4_t)__s1, __p2); \ ^ ~~~~ 2 errors generated.<o:p></o:p> </blockquote> <o:p> </o:p> clang14 does appear to support the vcopyq_laneq_u32() intrinsic, s0 we want to skip the conditional implementation.<o:p></o:p> Two approaches I have tested to resolve the error are:<o:p></o:p> 1) skip if building with clang:<o:p></o:p> <blockquote style="margin-top:5.0pt;margin-bottom:5.0pt"> #if !defined(__clang__) && ((defined(RTE_ARCH_ARM) && defined(RTE_ARCH_32)) || \ 72 (defined(RTE_ARCH_ARM64) && RTE_CC_IS_GNU && (GCC_VERSION < 70000))) <o:p></o:p> </blockquote> 2) skip if not building for ARMv7: <o:p></o:p> <blockquote style="margin-top:5.0pt;margin-bottom:5.0pt"> #if (defined(RTE_ARCH_ARMv7) && defined(RTE_ARCH_32)) || \ (defined(RTE_ARCH_ARM64) && RTE_CC_IS_GNU && (GCC_VERSION < 70000)) <o:p></o:p> </blockquote> Both address our immediate problem, but may not be a appropriate for all cases.<o:p></o:p> Can anyone suggest the proper way to address this? I'll be submitting an patch once I have a solution that is acceptable to the community.<o:p></o:p> Regards, Roger <o:p></o:p> <o:p></o:p> <o:p> </o:p> <o:p> </o:p> <o:p></o:p> </div> </div> </div> </div> </body> </html>